theres already been a load of discussion about which one is better.
in the end its about which brand you prefer more and who you trust more.
if you dont have any preferences then it will depend on the games you will be playing the most.
in your case the games too show no distinct advantage to either cards. so go for what your gut feels and you wont go wrong either way. also which one is cheaper and which brand has better service would also affect your decision.
both 660ti and 7950 are almost inseparable from each other. so no particular preference